Thomas a



(No Model.)

T. A. EDISON.

MANUPAGTURB OF INGANDESOING ELEGTRIO LAMPS.

No. 278,417,. Patented'May 29,1883.

ATTEST: INVEN'T OR:

UNITED STATES PATENT, OFFICE.

THOMAS EDISON, OF MENLO PARK,NEW JERSEY, ASSIGNOR TO THE EDISON ELECTRIC LIGHT COMPANY, OF NEW YORK, N. Y.

MANUFACTURE .OF INCAND ESCING ELECTRIC LAMPS.

SPECIFICATION forming part of fietters Patent No. 278,417, dated May 29, 1883. Application filed January 22, 1883. (No model.)

To all whom it may concern Be it known that I, THOMAS A.'EDISON, of Menlo Park, in the county of Middlesex and State of New Jersey, have invented a new and useful Improvement inthell/Ianufactnre of Incandescin g Electric Lamps, (Case No. 536,)of which the following is a specification.

In my application No.516 (Serial No. 77,526) is 'describedan incandescing electric lamp whose inclosing-globe contains. nitrogen at apressure which prevents electrical carrying from the carbon incandescing conductor.

The object of my present'invention is to provide a simple, economical, and efficient method ofintroducin g such a nitrogen atmosphere into such lamp-globes, the nitrogen admitted being pure and free from moisture, such method being also applicable wheuit is desired to charge any vessel or receptacle with any gas in a pure and dry condition. i

In applying, my invention to the purposes for which it is preferred, the nitrogen is evolved by heating a dry salt containing nitrogen, such as the nitrite of ammonia, or nitrite of potassium, or nitrite of chromium ,or certain mixtures maybe used which include such nitrites--for instance, a mixture ot' potassic nitrite and chloride ofammonia. The substances,- when heated, give oft'pure nitrogen. The lampglobe, when ready for exhaustion, is placed in connection with a Sprengel vacuum apparatus, from the exhaust-tube of which extends a tube which terminates in a bulb or chamber in which is placed the dry salt containing'nitrogen. The lamp and also thisbulb orchamher are then exhausted by the vacuum apparatus, with which both are connected, to as nearly complete a vacuum as possible, after which the action of said apparatus is stopped and the bulb or chamber is heated by a lamp, or in any suitable way. The compound is decomposed, and the nitrogen given off flows through the tube and into the lamp until the desired pressure is obtained, after which the lamp is sealed 0ft A portion of the tube through which the nitrogen flows, and which is exhausted. with the rest of the apparatus, contains phosphoric anhydride or otherdrying agent to take up the water of crystallization of the dry salt,the gas which enters the globe being thus free from moisture.

A convenient apparatus is illustrated in the nating in a bulb, G, which contains one of the substances or mixtures previously mentioned,

or other equivalent substance or mixture. The

tube b is provided with a bulb, d, which contains phosphoric anhydride or other drying agent. The operation of the apparatus is as before explained, the lamp being finally sealed off at I It is evident that this invention may be em- .ployed in charging any receptacle with any gas by heating a dry compound placed in said receptacle, which compound is' decomposable by heat into the gas required, and said receptacle being first exhausted.

\Vhat I claim is v 1. The method of charging a receptacle with pure gas, consisting in exhausting said receptacle to a high vacuum, and then heating a dry compound decomposable by heat into the gas required, said compound being placed within said receptacle, substantially as set forth.

2. The method of providing the exhausted inclosing-globe 0t an.incandescing electric lamp with an atmosphere of pure nitrogen, consisting in heatingadry salt capable of giving otl nitrogen when decomposed by heatin g, placed in an exhausted receptacleconnected with said lam p-globe, substantially as set forth.

3.'The method of providing the inclosingglobe of an incandescing electric lamp with an atmosphere of pure nitrogen, consisting in exhausting said globe and simultaneously ex hausting a receptacle connected therewith and containing a dry salt containing nitrogen and decomposable by heat, and then heating said receptacle, substantially as set forth.

This'specification signed and witnessed this 13th day of January, 1883.

THOS. A. EDISON.

Witnesses:

H. W. SEELY, EDWARD H. PYATT. 

